Automatic circuit breaker



Feb. 2, 1954 P. M. CHRISTENSEN AUTOMATIC CIRCUIT BREAKER 2 Sheets-Sheet 1 Original Filed Oct. 8, 1949 I N V EN TOR l a. E Z

PAUL M CHR/STENSEN BY 62M M ATTORNEYJ 5 i .MS a N wj 0 0 l F we 1 m A imm mwm F H 3 W 5 7 8 6 4 m 0 8? mw 1 m z a L H0 7 a O W F wOw. W; Z

Feb/L 1954 P. M. CHRISTENSEN 2,663,213

AUTOMATIC CIRCUIT BREAKER Original Filed Oct. 8, 1949 2 Sheets-Sheet 2 [611E INVENTOR. ,6 46 PAULA/I. CH/P/STENSEN F 1%-25 l G e ATT RNEYS Patented Feb. 2, 1954 AUTOMATIC CIRCUIT BREAKER Paul M. Christensen, West Orange, N. J., assignor to Federal Electric Products Company, Essex County, N. J a corporation of Delaware Original application October 8, 1949, Serial No.

120,361, now Patent No. 2,648,736, dated August 11, 1953.

Divided and this application April 10, 1952, Serial No. 281,588

10 Claims.

This invention relates generally to an automatic circuit breaker, and more particularly to a circuit breaker that is particularly adapted for motor starting and similar purposes.

The object of the present invention is the provision of a circuit breaker of generally simplified construction and design and of improved operation.

Another object is the provision of a circuit breaker having improved means for securing a cover plate thereto.

The above and other objects, features and advantages of the present invention will be fully understood from the following description considered in connection with the accompanying illustrative drawings.

In the drawings:

Fig. 1 is a front view of a circuit breaker embodying the invention, said circuit breaker being shown in the on or circuit-closed position;

Fig. 2 is a side View of the circuit breaker;

Fig. 3 is a rear view of the circuit breaker;

Fig. 4 is a bottom view of the circuit breaker;

Fig. 5 is a view similar to Fig. 1 showing the circuit breaker with the casing closure thereof removed;

Fig. 6 is a view similar to Fig. 2 with the closure removed;

Fig. 7 is a front View of the casing body with some parts in position therein;

Fig. 8 is a sectional view taken on the line 88 of Fig. 7;

Fig. 9 is a fragmentary sectional view taken on the line 99 of Fig. 7;

Fig. 10 is a sectional view taken on line Ill-Ill 1 of Fig. 1;

Fig. 11 is a fragmentary sectional View similar to Fig. 10 showing the circuit breaker in its off or circuit-open position;

Fig. 12 is asectional view taken on line l2|2 of Fig. 10; I

I Fig. 13 is a sectional view taken on line |3-|3 jof Fi .1;

Fig. 14 is a sectional view taken on line |4--I4 of Fig. 1;

Fig. 20 is a view similar to Fig. 5 showing another form of the invention.

Referring to the drawings, the circuit breaker 2| is housed in a casing 22 preferably molded from a suitable insulating material, said casing being preferably formed of the separate casing parts 24 and 26, the former part constituting an insulating casing block or body portion, the latter part constituting a closure therefor. These parts are connected by suitable means, such as screws 28, and together they constitute a housing enclosure i or the circuit breaker mechanism. As illustrated in Figs. 2 and 10 the front ends of screws 28 engage the brackets 30 and 32 which may serve as a means for supporting the circuit breaker. The circuit breaker may be mounted in a suitable enclosure or box, such as, for example, the box illustrated and described in the patent to Joseph Sachs, No. 2,094,963, dated October 5, 1937. For this purpose, the brackets 30 and 32 are provided with the apertures 34 and 36 respectively, for receiving screws or other suitable attaching elements. Provision is also made for attaching a standard flush-type wall plate or cover member to the circuit breaker. An example of such a wall plate 38 is illustrated, in broken lines, in Figs. 1, 2 and 10, it being noted that said plate may be attached by suitable means, such as screws 40, 40, which are engaged, respectively, in aperture 42 in bracket 30, and in the internally threaded upper portion 44 of a screw 46 hereinafter fully described.

The circuit breaker is provided with a pivoted handle or operating member 48 substantially centrally thereof. Said handle projects through a.

4 suitable slot 50 in the closure member 26. Due

to the central disposition of the handle, it will also project through the slot 52 in the standard wall plate 38.

The casing block 24 comprises the rear wall 54,

the opposing lateral walls 56 and 58, and the up- I per end wall 6!], saidblock being open at its lower ing longitudinally thereof and disposed substantially centrally between lateral Walls 56 and 58, said portion and said lateral walls defining the companion guideways 66 and 68, the function of which is hereinafter described. Extending outwardly from the opposing ends of said guideways, atthe sides thereof defined by ledge 64, are the companion pairs of guide parts, 10, I0, and l2, 12, respectively, said guide parts extending above the bottom surface of said guideways. It will be noted that ledge 64 is provided with a raised part I4 in which is defined a recess I6, open at the front thereof, and provided at its rear with .the opening 18 extending through rear wall 54, said recess extending between the guide parts I2, I2. Rear wall 54 is also provided, on its outer surface, with the recessed portions 80, 82 which communicate with the openings 84 and .86 respectively, extending through the rear wall, as illustrated in Figs. 3, 7 and 9, adjacent the lower end thereof. At said lower end, the rear wall is provided with an internally threaded bushing 83, which is positioned between ridges 90A and 96B, :and the raised marginal edge portions 92, 92 extending between said ridges and the side walls 56, 58, respectively.

The front of chamber 62 in the casing block is partially covered by the separate terminal members 94 and 96, respectively, at one side thereof, and by the unitary terminal member 98, on the other side thereof. As here shown, terminal member 94 is mounted on the casing block by a screw "NA and is provided with a conventional terminal screw I02A for connection to an electrical conductor. Terminal member 94 is also provided with a downwardly extending part I04 (Fig. 13) which carries a stationary contact I06, and with a laterally extending integral guide part I08A, as hereinafter described. Terminal member 96 is also secured to the casing block by a screw I B and is provided. with a terminal screw I02B. In addition, terminal member 96 is provided with an upwardly extending part or ear I IOA (Fig. 14) in which there is riveted an axially extending pintle II2A provided with a collar I I4A which abuts said ear. The terminal member 98 is mounted in the casing block by screws I000, 100C, in the same manner as terminal members 94 and 96 and is similarly provided with the spaced terminal screws I020, I02D. Said terminal member 98 is provided with a laterally extending integral guide part IOBB and with the ear IIOB in which there is riveted the axially extending pintle 23 provided with the collar II4B which abuts said ear.

Underlying terminal member 96, the casing block is provided with a contact member I I6 (Figs. 7, 8 and 13) which is mounted thereon by screw I I8. Said contact member is provided with a stal tionary contact I20, companionate tocontact I06. A conducting member or strap I22 is secured in the aforementioned recess 60, in the outer surface of rear wall 54, by the screw IIB which also secures contact member H6 in the block. Said strap extends through opening 84 in the rear wall and the free end I24 thereof, is secured against lateral movement on said rear wall by ridge 90B and lateral wall 53. A conducting strap I26 is secured in the recess 62 by screw IO0B which also secures terminal member 96 on the block. Said strap I26 extends through opening 86 and the free end I 28 thereof, is secured against lateral movement on the rear wall by ridge 90A and lateral wall 56.

An insulated movable contact carrier I28 (Figs. 16, 1'7 and 18) is disposed within chamber 62 for rectilinear movement in the casing block. Said 7 carrier is molded of insulation material and is provided with opposing walls I30 and I32 which are integrally joined with the axially extending cross part I34, said walls depending below said part and defining therewith the recess I36 (Figs. 12, and 18). Said walls are provided substantially midway of their lower marginal edges with the integral depending and laterally extending portions I33A and I38B, respectively. It will be noted that the bottom surface I40A and I40B, respectively, of said portions is provided with a downwardly extending portion I42A and I42B (Fig. 12) respectively, inwardly thereof. A thermostatically responsive element, here shown as the bi-metallic flexible strip or latch I44, is disposed in recess I36 and is secured at one of its ends to the upper end I46 of part I34. A rearwardly extending metallic lug I48 is also secured at said upper end, said lug clamping said bimetallic strip to the carrier. At its lower end I 49, part I34 is slotted, as at I50. A transversely extending pivot pin I52 is secured in said lower end and extends across said slot. Actuating means comprising a lever I54 is provided at one end with a tooth or latch member I56 and at its other end with an apertured portion I58, and is mounted intermediate its ends, in said slot for pivotal movement on said pi-n.

A helical compression spring I60 is vertically disposed in the aforementioned recess "I6, and when the movable contact carrier is positioned in the casing block, as shown in Figs. 10 and 11, the lug I48 engages the upper end of the spring. It will be understood that the spring may be inserted in the chamber through the opening I8 and that it will be retained in vertical disposition therein by the walls thereof. To facilitate the disposition of the lug on the upper end of the spring, any suitable tool may be inserted through the opening 10 for depressing the spring as the lug is inserted in the chamber. It will be understood that the spring is compressed by the lug during the downward movement of the carrier and biases the carrier to its normal or retracted position, said position representing the off or open condition of the circuit breaker as hereinafter described.

When the movable contact carrier is mounted in the casing block, the portions I38A and I38B, thereof, straddle the raised portion I4 of ledge 64, as shown in Fig. 12, said raised portion constituting the front wall of chamber 16. The bight of a U-shaped conducting member or strap I62 (Figs. 12 and 13) is disposed on the upper surface of the previously mentioned guideway 66 and is retained thereon, between the depending portion I42A and the lateral wall 56, by part I38A, the sides of said part being straddled by the upwardly extending flexible arm of said conducting member. Said arms are provided, at the upper ends thereof with the movable contacts I64A and H543 which cooperate with the fixed contacts I20 and I06, respectively. It will be apparent that when the movable contact carrier is subjected to the rectilinear motion thereof, as will hereinafter appear, the parts I38A and I383 move in the guideways 66 and 68, respectively, and are retained against lateral movement by the lateral casing-block walls and ledge I4. It will be apparent that during such movement, the conducting member I62 is carried by part I36A from the position, indicated in broken line in Fig. 13, wherein the movable contact I64A and I64B are disengaged from the stationary contacts I26 and I06, respectively, to a position in which the cooperating contacts are engaged, as illustrated in said figure. It will be understood that when the movable contacts engage the stationary contacts, the arms of the conducting member flex to provide a resilient perssure of said movable contacts against said stationary contacts, respectively, During said movement of the contact carrier, the lower marginal edge portions of the walls I38 and I32 of the carrier serve as runners or slides to facilitate the rectilinear travel of the carrier. Specifically, the rearward runner portions I3ilA and IS'ZA, of carrier side walls I38 and I32, respectively, slide on the aforementioned rearward guide parts 12, 12, as illustrated in Fig. 19, the adjacent side wall portions being retained against lateral movement by the side walls 56 and 58, respectively, of the casing block. The forward runner portions I383 and I323, of the respectiv carrier side walls, similarly serve as runners or slides and slide on the aforementioned forward guide parts 18, 18, as illustrated in Fig. 15, and the adjacent side Wall portions are similarly retained against lateral movement by the side walls 56 and 58, respectively, of the casing blocks. During said movement, the upper marginal edges IfiiiC and I320, respectively, of the carrier walls are guided and retained in the block by the completely overlying guide parts I88A and I 885 of terminal member 94 and 98, respectively, as illustrated in Figs. 5, 12 and 19, and by the partially overlyin portions 96A and 98A of terminal members 96 and 98, as i1 lustrated in Figs. 5 and 15.

In the normal or closed condition of the circuit breaker, the stationary contacts I28 and I06 are engaged by the movable contacts IEAA and I54B, respectively, to Complete an electrical circuit through the circuit breaker. Assuming that the terminal screws I82A and I 820 are connected to the power line and that a suitable load is connected to the terminal screws I 82B and I82D, respectively, the circuit is completed from one end of the power line through terminal member 94, engaged contacts I88 and I64B, through the movable contact member I62, through engaged contacts [64A and I20, through the contact member H8, through screw H8, through strap I22, through a heater unit I86, hereinafter described, and to the terminal screw IDZB of terminal member 96, to which on side of the load is connected. The other end of the power line is connected directly to the load through the terminal member 98.

The heater unit I68 may be of any suitable type wherein the passage of current therethrough generates heat. As here shown (Figs. 4 and 10) said heater is provided with an insulated body portion I68 which is secured in the aforementioned bushing 88 in the casing block by the externally threaded portion of the aforementioned screw 46, the upper internally threaded portion 44 of said screw serving to secure the wall plate or cover member 38 to the circuit breaker, as previously described. The heater is provided with the contacts NBA and H553 which engage the free ends of straps I28 and I22, respectively, the heater element I12 being connected to the contacts by suitable conducting portions I14. As shown in Fig. 10, the heater element extends into the casing block from the open end thereof, and underlies the previously mentioned flexible bi-metallic latch I 44.

For actuating the movable contact carrier for normal switching purposes, or to eifect closing of the circuit after the automatic opening thereof, there is provided the aforementioned handle or actuating element 88 which is provided with means for effectin the rectilinear movement of the movable contact carrier. As here shown (Fig. 14), the handle is provided with a bearing bore I16 in which are disposed the aforementioned pintles II2A and 23, the handle being piv-' otally rotatable about said pintles. The portions MBA and IUBB of terminal members 94 and 88, respectively, serve as a detent or stop for the handle when rotated to the circuit closing position, as shown in Fig. 12, the hub of said handle being provided with cut-out portions I18, I18 which engage said terminal member portions. When the handle is rotated to the open circuit position of the circuit breaker, a detent or stop is provided therefor by th apertured end I58 of lever I54, as illustrated in Fig. 11. The handle is biased to the open circuit position thereof by a torsional spring I88 which is positioned about the lateral handle hub I82, one end of said spring being engaged in the opening I84 in the handle and the other end thereof being secured to the aforementioned ear IIllA (Figs. 5 and 14). Operating means comprising a link I88 (Fig. 5) interconnects the handle and lever I54, said link being pivoted to the handle at I 88 and pivoted to the lever at I58. Under normal conditions, i. e., in the absence of flexing of strip I44 upon overload, the tooth I58 of the lever I54 is engaged by the wear piece I98 at the free end of the bi-metallic latch I44, as illustrated in Fig. 10, and the handle is thereby operatively connected to the movable contact carrier for moving the latter, the spring I88 biasing the carrier to the circuit open position, as heretofore described.

When the bi-metallic latch is engaged by the lever, as in Fig. 10, link I88 cooperates with the handle to form a toggle. As the handle is rotated to the on, or closed circuit position, as illustrated in Fig. 10, the handle part I 88 is moved forwardly from the position illustrated in Fig. 11 to the position illustrated in Fig. 10, and the link, being engaged in said part, transmits the forward motion to the lever which is carried by the movable contact carrier, the lever being retained against pivotal movement by its engagement with latch I44 and serving to move the carrier to its operating position. During said movement of the carrier, the movable contact member I62 is carried along guideway 86 by the part I3BA to move contacts I84A and 5513 into firm engagement with the fixed contacts I28 and I86, respectively. It will be understood that the above described toggle action of handle 48 and link I88, in the overcentered condition of the toggle (Fig. 10), is sufficiently strong to resist both the tendency of the spring I69 to move the carrier to the off position and the tendency of spring I88 to move the handle to said position. It will be observed, however, that until bimetallic strip I44 flexes and releases lever I54, spring I68 maintains the toggle in overcentered condition against the action of handle spring I88.

The above described toggle action can be released by pressing the handle downward, the parts then moving under the action of both springs to the open circuit condition shown in Fig. 11, it being understood that the lever normally remains in engagement with the latch I44 in said position. The movable contacts IEAA and IMB are thus disengaged from the cornpanion stationary contacts and the circuit is broken in two separate places thereby. By mov ing the handle toward the upward position the several parts can be restored to their respective closed-circuit positions, as shown in Fig. 10, and the circuit can thus be re-established.

As before explained, the bi-metallic strip I44 overlies the heater element I12 which is electrically connected in series with both the movable and. fixed contacts. Said strip is adapted to be deflected rearward as illustrated in Fig. 11) upon the passage of excess current through the heater element with the result that the wear piece I98 is disengaged from the tooth I56 of lever I54 and the carrier is freed for movement by spring I60 to disengage contacts IMA and IfiiB from stationary contacts I20 and I96. It will be noted that when strip I44 disengages lever I54 the toggle constituted by the handle and by link I86 collapses and spring I39 is thereupon effective to move the handle to its off position and to position the end I55 of lever I54 so that it can engage the end piece I90 of bi-metallic strip I44, when the latter flexes back to its normal condition. upon cooling, to re-close the circuit breaker by movement of the handle to its on position. It will be noted also that the handle 4% is in trip-free relation to carrier I28 and accordingly that even if the handle were held stationary during the occurrence of an overload, this would not prevent or otherwise interfere with the automatic opening of the circuit breaker.

Means for calibrating the circuit breaker is provided by the screw I92 (Figs. and 11) which engages the movable contact carrier and the thermostatic strip I44 near the fixed end thereof. It will be understood that the free end of the strip may be moved closer to, or farther away from, the lower surface of cross-part 53d of the movable contact carrier thereby requiring an increased or decreased deflection, as the case may be, to unlatch the strip.

In the form of the invention illustrated in Fig. 20, the circuit breaker is converted from the previously described single-pole switch into a doublepole switch thereby providing for two additional breaks on the other side of the circuit in the open condition thereof. As here shown, the unitary terminal member 98 is replaced by a pair of terminal members 99A and 9913, provided with the terminal screws I026 and MD, respectively. Terminal member 99A is in all respects the same as terminal member 94 being provided with an integral stationary contact I06 and terminal member 99B is in all respects similar to terminal member 96 except that it is provided with an integral stationary contact I94. It will be understood that an additional movable contact memher I 62A is now provided which is carried by the part I38B in the same manner as the contact member I52 is carried by the part ISSA. It will be apparent that in the closed circuit condition, the stationary contacts m6 and I94 are engaged by the movable contacts I64B and IMA, respectively, to complete a circuit between one side of the power line'connected at I020 and one side of the load connected at I02D. It will be apparent that when the circuit breaker is moved to its open-circuit condition, as heretofore described, there will be two breaks in said side of the line, when the contacts are disengaged. If preferred, an insulating strip I96 may be positioned across terminals 94 and 99A as shown in Fig. 20.

This application is a division of my application gear. No. 120,361, filed October 8, 1949, which has matured into United States Patent No. 2,648,736.

While I have shown and described the preferred embodiment of my invention, it will be understood that various changes may be made in the present invention without departing from the underlying idea or principles of the invention within the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent, is:

1. In an automatic circuit breaker having a casing and adapted for use with a cover member, a contact carrier movable in said casing, actuating means for said carrier, a thermostatic latch releasably interengaging said actuating means andsaid carrier in the normal load conditions of the circuit breaker and operable upon overload to release said actuating means for movement of the carrier to open the breaker, and a heating device for said latch; means for removably mounting said heating device in operating position in relation to said latch in said casing, said mounting means having means for removably securing said cover member to said circuit breaker.

2. In an automatic circuit breaker having a casing and adapted for use with a cover member, a contact carrier movable in said casing, ctuating means for said carrier, a thermostatic latch releasably interengaging said actuating means and said carrier in the normal load conditions of the circuit breaker and operabl upon overload to release said actuating means for movement of the carrier to open the breaker, and a heating device for said latch; means for removably mounting said heating device in operating position in relation to said latch in said casing comprising a member carried by said heating device, said member having a portion releasably engageable in said casing and a portion adapted to removably receive a cover-member securing element.

3. In the combination of a circuit breaker casing and a cover member adapted to overlie the casing wherein the circuit breaker is provided with thermostatic control means and a heater therefor, a mounting member for mounting said heater in said casing relative to said control means, said mounting member having an end portion releasably engageable in said casing and an end portion for securing said cover member thereto.

4. In the combination of a circuit breaker casing and a cover member adapted to overlie the casing wherein the circuit breaker is provided with thermostatic control means and a heater therefor, a mounting member for mounting said heater in said casing relative to said control means, said heater having an insulated portion through which said mounting member extends so that opposite end portions of said mounting member project from opposite sides, respectively, of said insulated portion, one of said end portions being releasably engageable in said casing, and the other of said end portions having provision to secure the cover member relative to the casing.

5. In the combination of a circuit breaker casing and a cover member adapted to overlie the casing wherein the circuit breaker is provided with thermostatic control means and a heater therefor, a mounting member for mounting said heater in said casing relative to said control means, said heater having an insulated portion through which said mounting member extends so that opposite end portions of said mounting member project from opposite sides, respectively, of said insulated portion, one of said end portions being externally threaded for threaded engagement with said casing, and the other of said end portions being internally threaded for securing said cover member thereto.

6. A heater assembly for a circuit breaker, said heater assembly comprising a heating element,

an insulated portion for mounting said heating element and a mounting member for securing the heater assembly in the circuit breaker, said member extending through said insulated portion with the ends thereof projecting from opposite sides, respectively, of said insulated portion, one of said ends being externally threaded for threaded engagement with a circuit breaker casing, and the other of said ends being internally threaded for securing a cover member thereto in disposition relative to the casing.

7. A heater assembly for a circuit breaker, said heater assembly comprising a heating element, an insulated portion for mounting said heating element and a mounting member for securing the heater assembly in the circuit breaker, said member extending through said insulated portion with the ends thereof projecting from opposite sides, respectively, of said insulated portion, one of said ends being externally threaded for threaded engagement with a circuit breaker casing, and the other of said ends being internally threaded for securing a cover member thereto in disposition relative to the casing, said other end having a screw-driver slot.

8. A heater assembly for a circuit breaker, said heater assembly comprising an insulated part provided with an upwardly extending portion, a heating element extending from said part transversely of said portion and a mounting memher for said heater assembly, said member being disposed in said upwardly extending portion and having opposite end parts projecting therefrom, one of said end parts being externally threaded and the other of said end parts being internally threaded.

9. A heater assembly, as defined in claim 8, wherein said other end part is provided with a screw-driver slot.

10. A heater assembly, as defined in claim 8, wherein said heating element is secured to spaced portions of said insulated part and said mounting member is an axially extending element disposed intermediate said spaced portions.

PAUL M. CHRISTENSEN.

Referenees Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,198,502 Leland Apr. 23, 1940 2,439,338 Fuge et al Apr. 6, 1948 2,486,888 Schleicher Nov. 1, 1949 

